Government borrowing increased last month after the state was forced to pay higher interest on its debt.Public sector net borrowing, excluding state-owned banks, rose to £6.9bn in June, up £2bn from a year earlier.The government's debt costs jumped by more than a third in June from a year earlier after rising inflation pushed up interest on index-linked bonds.For the financial year to date, borrowing is up £1.9bn to £22.8bn, the Office for National Statistics said.The Office for Budget Responsibility (OBR) - the fiscal watchdog - has forecast that borrowing will be £58.3bn during the current financial year. In the financial year to March 2017, borrowing was £46.2bn according to the latest estimates from the ONS.